The promise of pharmacogenetics: assessing the prospects for disease and patient stratification.

Pharmacogenetics is an emerging biotechnology concerned with understanding the genetic basis of drug response, and promises to transform the development, marketing and prescription of medicines. This paper is concerned with analysing the move towards segmented drug markets, which is implicit in the commercial development of pharmacogenetics. It is claimed that in future who gets a particular drug will be determined by their genetic make up. Drawing on ideas from the sociology of expectations we examine how pharmaceutical and biotechnology companies are constructing, responding to and realising particular 'visions' or expectations of pharmacogenetics and market stratification. We argue that the process of market segmentation remains uncertain, but that the outcome will be fashioned according to the convergence and divergence of the interests of key commercial actors. Qualitative data based both on interviews with industry executives and company documentation will be used to explore how different groups of companies are developing pharmacogenetics in distinct ways, and what consequences these different pathways might have for both clinical practice and health policy. In particular, the analysis will show a convergence of interests between biotechnology and pharmaceutical companies for creating segmented markets for new drugs, but a divergence of interest in segmenting established markets. Whilst biotechnology firms have a strong incentive to innovate, the pharmaceutical industry has no commercial interest in segmenting markets for existing products. This has important implications, as many of the claimed public health benefits of pharmacogenetics will derive from changing the prescribing of existing medicines. One significant implication of this is that biotechnology companies who wish to apply pharmacogenetics to existing medicines will have to explore an alternative convergence of interests with healthcare payers and providers (health insurers, HMOs, MCOs and national health systems). Healthcare providers may have a strong incentive to use pharmacogenetics to make the prescribing of existing medicine more cost-effective. However, we conclude by suggesting that a question mark hangs over their ability to provide the necessary economic and structural resources to bring such a vision to fruition.